The general purpose of this study is to use the self-regulation of exercise maintenance model to clarify the exercise experiences of women and men who are 78 years old and older. The self-regulation of exercise maintenance model focuses on interpretations. Interpretation is defined as the awareness of sensations, the thoughts and feelings associated with exercise, and the meaning assigned to exercise. Episode-specific interpretations are concrete and occur during and after an episode of exercise. General interpretations includes the conceptual meaning of and beliefs about exercise. Using a prospective longitudinal design, this study includes four specific aims: 1) To describe and compare what individuals who are 78+ years old expect of a supervised exercise program before they begin exercising and, after the program, how they perceive these expectations were met; 2) to examine the difference between expected interpretations and episode.specific interpretations for maintainers as compared to dropouts of the supervised exercise program; 3) to examine the temporal relationships among episode-specific interpretations, general interpretations, and exercise behavior; 4) to examine the difference in general and episode.specific interpretations for maintainers compared to dropouts of a supervised exercise program. If this self-regulation model is supported, nurses working with older individuals such as those in home health, nursing homes, or patient education, can develop and test interventions (e.g., cognitive restructuring, positive self-talk) to restructure episode.specific interpretations of exercise during actual episodes of exercise. Positive interpretations of exercise behavior and negative interpretations when exercise is missed may reduce the number of dropouts once initiation has taken place.